The other day I did a little "research" in the few forums dedicated to Romanian webmasters to observe as much as possible what are the criteria according to which a person chooses to buy a backlink for his website or online store.
I was not very surprised when I noticed that, for most of the so-called forum members, the basic aspect were the Page Authority , Domain Authority , in some cases even Page Rank (which, be careful, has not been updated for several years) and probably the factor that most influences the choice: the price of a link.
The value of a link consists, categorically, in the quality of the site on which it is inserted. So the value of a site is directly proportional to the value of a link placed on that site, with small exceptions depending on the niche, here talking about related links that I will describe a little later.
The first criterion according to which we can analyze part of the value of a website is the quality of the links that come to the site we are talking about, implicitly their age and their anchors. The more "heavy" a site has behind it, the more profitable a link on that site will be.
After you have made sure that the place where you want to buy a link for a certain period has quality in terms of backlinks, it is time to check the on-site part a little, that is, the internal and external links within it. If a site has a large number of external links (leading to other web addresses) compared to articles without links, then it can be considered a link farm and therefore its value decreases from the start.
However, a factor that increases quality is represented by internal links (those that lead to other pages of the same site). These are beneficial from all points of view (although you should never choose the option of excess in this case) and you do not have to worry if there are internal links to the page where you want to buy a link.

Link juice – What is it and what does it help with?

One of the methods to "help" your site to some extent from an SEO point of view is represented by Link juice or "juicy link", in translation. This means, in Romanian, that a link goes from your site to a very high quality site. Attention. External links are different from Link juice and should not be confused. A link for which you are paid a few tens of euros to insert it in an article will not help you at all. On the other hand, if you slip a link to Wikipedia, Google or other valuable sites somewhere, you can expect pleasant surprises if your site is just starting out.

My opinion, in brief, about PA/DA metrics

As I said in the first part of the article, these 2 metrics are by no means the key factor that we should rely on when purchasing a link .
The only reason why I check, however, with MOZ these 2 measurements is that they show – to some extent – ​​whether the site is growing or declining. Indeed, this is more of a “guess” because MOZ only uses a part of the links so the rest can represent a huge decrease or an equally large increase so, in the end, it is best to ignore these factors and rely only on the advice that I gave in the first part of the article.